An inkjet recording device that discharges ink from multiple nozzles of an inkjet head to record an image on a recording medium is well known. For example, an actuator type inkjet head where a piezo actuator that transforms when voltage is applied is placed in each pressure chamber that connects to a nozzle is well known as an inkjet head. This inkjet head is manufactured using a semiconductor process where pressure chambers, and piezo actuators corresponding respectively to the pressure chambers, are arranged on a silicon wafer.
One problem with this type of inkjet head in that when discharge droplet volumes from the nozzles are not uniform, concentration distribution occurs in an output image and thus image quality drops. To address this problem, measures are taken to correct variations in ink discharge droplet volumes.
For example, a technique to address this problem includes measuring the thickness of a piezoelectric body film, determining widths for individual electrodes based on the amount of deviation between the thickness of the measured piezoelectric body film and a preset reference thickness, and then forming individual electrodes having the determined widths to then correcting variations in the thickness of the piezo electric body film using the widths of the individual electrodes.
Furthermore, another solution to this problem includes forming a cutout portion to reduce an area of a common electrode, placed on an ink pressure chamber corresponding to a nozzle targeted for a discharge rate adjustment, to correspond to a rate adjustment amount to reduce the transformation amount of a piezo electric element in that region, and thus make an ink discharge rate uniform.
The two solutions described above require measurements of variations in the thickness of a piezoelectric body film relative to individual elements and of an ink discharge rate, and thus the correction processes thereof are complex. Additionally, there is also a lack of any technical concept for changing a position of an inflection point of a displacement profile of a piezoelectric element.